Temperature sensing circuit for igbt module

Abstract

A temperature sensing circuit for an insulated gate bipolar transistor (IGBT) module, which enables a temperature of the IGBT module to be sensed by a pulse width modulation (PWM) method, using a photo coupler, etc., is provided. In the temperature sensing circuit for the IGBT module, a voltage value between both terminals of a diode is measured, the measured voltage value is converted into a digital signal, using a pulse width modulation (PWM) technique, and the converted digital signal is easily transmitted to a controller such as a microcomputer (MICOM), using a photo coupler for electrical insulation, so that it is possible to analyze the duty of the digital signal, thereby sensing an accurate temperature.

What is claimed is: 
     
         1 . A temperature sensing circuit of an insulated gate bipolar transistor (IGBT) module, comprising a temperature sensing circuit module built in the IGBT module,
 wherein the temperature sensing circuit module includes:   one or more diodes integrated within the IGBT module;   an encoder that measures a voltage value between both terminals of the diode when current flows through the diode, and converts the measured analog voltage value into a digital signal;   a decoder connected to be insulated from the encoder, to measure the voltage value between both the terminals of the diode, based on the digital signal from the encoder;   a photo coupler connected between an output terminal of the encoder and the input terminal of the decoder to enable a signal to be transmitted while in an insulation state therebetween; and   a microcomputer (MICOM) translating, into a temperature, the voltage value between both the terminals of the diode, provided by the decoder.   
     
     
         2 . The temperature sensing circuit of  claim 1 , wherein the diode and the encoder are integrated within the IGBT module, and the decoder and the MICOM are integrated on the outside of the IGBT module. 
     
     
         3 . The temperature sensing circuit of  claim 1 , wherein, when a plurality of temperature sensing circuit modules exist, decoders of the temperature sensing circuit modules are simultaneously connected to the MICOM with one wire, using a wired-OR technique. 
     
     
         4 . The temperature sensing circuit of  claim 1 , wherein a first amplifier is connected between the output terminal of the encoder and an input terminal of the photo coupler, a second amplifier is connected between an output terminal of the photo coupler and the input terminal of the decoder, and a third amplifier is connected between an outer terminal of the decoder and an input terminal of the MICOM. 
     
     
         5 . A temperature sensing circuit module comprising:
 one or more diodes integrated within an IGBT module;   an encoder connected between both terminals of the diode to measure current flows through the diode to measure an analog voltage value, and convert a measured analog voltage value into a digital signal;   a decoder insulated electrically from the encoder, configured to measure the voltage value between both the terminals of the diode, based on the digital signal from the encoder;   a photo coupler connected between an output terminal of the encoder and the input terminal of the decoder; and   a microcomputer (MICOM) translating, into a temperature, the voltage value between both the terminals of the diode, provided by the decoder.   
     
     
         6 . The temperature sensing circuit module of  claim 5 , wherein the diode and the encoder are integrated within the IGBT module, and the decoder and the MICOM are integrated on the outside of the IGBT module. 
     
     
         7 . The temperature sensing circuit module of  claim 5 , wherein, when a plurality of temperature sensing circuit modules exist, decoders of the temperature sensing circuit modules are simultaneously connected to the MICOM with one wire, using a wired-OR technique. 
     
     
         8 . The temperature sensing circuit module of  claim 5 , wherein a first amplifier is connected between the output terminal of the encoder and an input terminal of the photo coupler, a second amplifier is connected between an output terminal of the photo coupler and the input terminal of the decoder, and a third amplifier is connected between an outer terminal of the decoder and an input terminal of the MICOM.